Abstract
Human ether-a-go-go-related gene (hERG) channel plays an essential role in the repolarization of the cardiac action potential. Genetic mutations and some chemicals/drugs interfere with hERG channel activity, which may prolong the QT interval and potentially cause long QT syndrome. The FluxOR™ thallium flux assay performed in two cell lines, U2OS and HEK293, with stable hERG expression can be used to identify compounds that inhibit hERG channel activity. This chapter describes a cell-based hERG channel inhibition assay that has been optimized and performed in a 1536-well plate format. The homogeneous and robust assay can be used to identify compounds that inhibit hERG channel activity.